sub-traction

Controls

• Arrow keys / swipe (mobile): move tiles up/down/left/right
• Space / press and hold (mobile): wait one turn (will spawn two new tiles)

Your goal: clear the board.

You accomplish this by smushing tiles into others with lesser/equal values. Doing so destroys the smaller tile and weakens (subtracts from) the larger tile by the smaller one's value.

Things to know:

• A new tile will be added if you fail to remove at least one piece on a single turn
• The new tile's value and position are denoted in the sidebar and by the empty grey border respectively
• Occupying the new tile's future position results in a new position being chosen
• There will always be at least two tiles on the board (creating one when necessary)
• Smushing is done from largest to smallest (7 is handled as far as it can go before 3 is considered)
• Mobile gestures are handled once your finger leaves the screen (i.e. press and hold will wait one turn once you raise your finger)

Tile smushing is resolved like so: (a smushing into b i.e. if moving left, a is on the right of b)